Transthecal Metacarpal Block Versus Traditional Digital Block for Painful Finger Procedures in Children

Background: Finger injuries and infections are common presenting problems in the pediatric emergency department. A traditional digital block, requiring at least two injections of anesthetic, is the traditional method of regional anesthesia for many finger procedures. Digital blocks can sometimes be difficult to administer and assess for effectiveness especially in children. A newer procedure, the transthecal metacarpal block, may be easier to administer, and more effective with one injection.

Objective: To determine if the transthecal metacarpal block (MCB) provides superior digit anesthesia in children requiring painful finger procedures as compared to the traditional digital block (TDB).

Methods: A randomized clinical trial comparing the MCB to the TDB will be conducted in an urban, tertiary care pediatric emergency department. Children <18 years of age, presenting to the emergency department with a finger injury or infection, which requires regional anesthesia for repair will be screened for eligibility. Eligible patients, with appropriate consent will be randomized to receive either the MCB or TDB with 1% Lidocaine. The primary outcome, success of the block will be assessed using pinprick testing after a standardized wait time. Secondary outcomes including pain with the block and repair, repairing physician satisfaction, and short-term complications will also be assessed.

Implications: Finding successful methods of anesthesia and pain control are paramount in the pediatric emergency department. In addition, using a type of digital block which is easy to administer, successful, and requires only one injection would give physicians confidence to treat finger injuries in children with regional anesthesia and possibly avoid procedural sedation in some cases. To date, no studies have been published on the efficacy of digital blocks in children. This study will also serve to give baseline success rates for both types of digital blocks.

Inclusion criteria

• Age <18 years
• Greater than 10 kg in weight
• Have finger injuries or infections that will require digital regional anesthesia
• Require only local anesthesia for the repair
• English speaking

Exclusion criteria

• Have previous participation in this study
• Need procedural sedation at the onset of the repair
• Have allergy to lidocaine or amide-type local anesthetics
• Have infection at the sites of block injection
• Have known coagulopathy